220-1101 Hardware and Network Troubleshooting Practice Question
A technician replaced a damaged Cat5e patch cable that connected a workstation to a wall jack. After replacement, the workstation reports a network connection speed of 100 Mbps instead of the expected 1 Gbps. Both the workstation's NIC and the switch port support 1 Gbps. Which of the following is the MOST likely cause of the reduced speed?
⚠ Common exam trap
Test-takers frequently assume any 'Cat5' cable is sufficient for gigabit speeds, but the exam tests the specific distinction that Cat5 is only certified for 100 Mbps, while Cat5e is the minimum for 1 Gbps over twisted-pair copper.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The new cable is a Cat5 cable instead of Cat5e
Cat5e cable is rated for 1 Gbps (1000BASE-T) up to 100 meters, while Cat5 cable is only certified for 100 Mbps (100BASE-TX) over the same distance. Using a Cat5 cable instead of Cat5e forces the auto-negotiation process to fall back to the highest common denominator supported by the cable, which is 100 Mbps. This explains why the workstation reports 100 Mbps despite both the NIC and switch port supporting 1 Gbps.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The new cable is a crossover cable
Why it's wrong here
While a crossover cable swaps the transmit and receive pairs, modern Gigabit hardware includes Auto-MDIX, which automatically detects and compensates for crossover connections. Even if Auto-MDIX were disabled, the result would be a failed link or continuous errors, not a clean reduction in negotiated speed to 100 Mbps. The link speed is determined by cable category compliance and supported speeds, not by the pinout arrangement.
- ✗
The new cable exceeds the maximum length for 1 Gbps
Why it's wrong here
A longer-than-specified cable would not cause a simple 100 Mbps fallback; both 100BASE-T and 1000BASE-T support a 100-meter channel limit, and exceeding that causes excessive attenuation, CRC errors, or no link at all. A typical replacement patch cable is only a few meters long, well within the standard. The observed behavior of a stable 100 Mbps link with a new cable strongly points to a cable category mismatch rather than length.
- ✗
The switch port is configured for 100 Mbps only
Why it's wrong here
If the switch port were configured for 100 Mbps, all devices on that port would be limited, but the issue appeared immediately after cable replacement, and the port previously supported 1 Gbps with the old cable.
- ✓
The new cable is a Cat5 cable instead of Cat5e
Why this is correct
A Cat5 cable is only certified to carry 100BASE-TX (100 Mbps) and lacks Cat5e's stricter crosstalk and performance margins needed for 1000BASE-T. When a Cat5 cable is connected, during auto-negotiation the attempt to establish a 1 Gbps link fails because the physical layer cannot meet Gigabit requirements, so both devices negotiate down to the highest common supported speed, 100 Mbps. The jacket marking on the new cable (Cat5 rather than Cat5e) would confirm this.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.